Please read “Installing Air via WordPress” firstly to learn about how download the installable file “air-theme2.zip”.
Use FTP client
Please download to install an FTP client such as FileZilla.
Upload the files
Please unzip the installable file “air-theme2.zip” to get the air-theme2 folder

Please upload the folder “air-theme” to your themes directory.
Active Air theme
After uploading the files, login to your WordPress admin.Please go to “Appearance > Themes”. Click “Activate” for the theme “Air”.
Return to the original article to read more about other steps(install plugin, import demo)